Apparatus for trimming molded articles



June 18, 1957 A. SAINT-ANDRE APPARATUS FOR TR IHMING MOLDED ARTICLES Filed July 6, 1955 United States Patent 9 M APPARATUS FOR TRIMlVIIN G MOLDED ARTICLES Alcide Saint-Andre, Romans, France Application July 6, 1955, Serial No. 520,310 Claims priority, application France .luly 15, 1954 4 Claims. (Cl. 30-263) The trimming of rubber or the like materials after molding is generally performed by means of manual or mechanical shears. Manually operated shears allow only a slow operation and lead speedily to fatigue for the operator. On the other hand, mechanical shears although they allow a speedy work are however unsatisfactory by reason of the diliiculty of obtaining with a simple structure reciprocating movements at a rapid rhythm. Furthermore, shears whether manually or mechanically controlled can never follow outlines which are very sinuous and they do not allow closely approaching the surface of the article to be trimmed. My invention has for its object to remove such drawbacks by means of a trimming apparatus including chiefly a blade system assuming a continuous high-speed circular movement; said blade system includes one or more elementary knives rotating round a common axis inside a cage section forming a chaser acting as a counterblade and the inner outline of which is also circular while its diameter is higher than that of the circle described during rotation by the end or ends of the knife or knives: said circles are tangent to each other at the actual cutting point where there is constituted in practice a Slot formed in the cage section registering with said point of tangency and through which the burr to be trimmed ofi the material is engaged.

Said slot, which has obviously a breadth of a magnitude of one or a few millimeters, is shifted with reference to the radius at the point of tangency whereby, taking into account the direction of rotation of the blade, one of the edges of the slot is brought to register with said radius i. e. one of the edges of the slot coincides with the radius which is orthogonal at the point of tangency with the tangent. Said arrangement allows bringing very near each other, without any contact however therebetween, the ends of the knives and the inner surface of the counterblade which cuts out the possibility of any dry contact and therethrough of any mechanical wear.

in a preferred embodiment of my improved apparatus, the cage forming the counterblade chase is constituted by two sections, which allows adjusting the breadth of the slot while the blade system includes two knives carried by a common plate, revolubly driven by a yielding transmission and carried inside a body serving as a carrier for the hand-operated control of the tool.

According to an auxiliary feature of my improved trimming apparatus, its knives play simultaneously the part of fan blades so as to produce simultaneously with a cooling of the body of the machine, a centrifugal blowing away of the waste material produced.

Lastly, it should be noticed that the outline of the knives which matches exactly the inner outline of the cage is such that it is possible through a mere change of the slope of the apparatus to follow any desired outline.

I will now disclose by way of example and by no means in a binding sense a preferred embodiment of my improved trimming apparatus. In accompanying drawings illustrating said embodiments:

2,795,849 Patented June 18, 1957 Figs. 1 and 2 are respectively an elevational view and a sectional view through line IIII of Fig. 1.

Fig. 3 is on an enlarged scale a plan view showing the blade and the counterblade chaser.

The tubular body 2 forming a handle carries inside 'it a spindle 3, said spindle 3 being revolubly mounted inside the needle rollers 4 and being driven through its end 5 by a yielding transmission which is not illustrated.

To the other end of said spindle 3 is keyed a plate 6 carrying two knives 7. These two knives are given the outline illustrated in Figs. 2 and 3 and revolve inside a cage section 8 forming a counterblade and the inner transverse outline of which is arcuate while its longitudinal outline matches that of the knives 7.

It should be remarked that, as illustrated in Fig. 3, the diameter of the circle of which the outline of the cage section 8 forms part is somewhat larger than the diameter of the circle 9 defined by the revolution of the rotary knife 7, while the first mentioned circle associated with the cage section 8 is eccentrically disposed to the circle 9 and is tangent at 10 to the circle 9, said point of tangency 10 forming the point at which the cutting is performed. The center of the first mentioned circle is located, for example, at the point 20 In order to provide for the engagement of the burrs to be trimmed inside the apparatus, the cage section 8 is provided with a longitudinal slot 12 designed in a manner such that one of its edges corresponds with the radius of the circle 9 which is orthogonal to the tangent at the point of tangency 10, while its other edge 12a is located at a distance from said radius which is of a magnitude of one or a few millimeters.

In order to allow furthermore the breadth of said slot to be adjusted as a function of the breadth of the burrs to be removed from a molded article. the cage section 8 includes two separate sections, of which one 8b is rigid with the body 2, since it carries the edge 12b of the slot i. e. the edge which is to occupy any unvarying well defined position while the other section 8 of the cage is adjustably mounted on the body 2 of the apparatus.

For this purpose, section 8 comprises elongated slots 16 through which extend the shanks of the bolts 17.

The trimming of molded articles through such an apparatus is extremely simple. It is sufficient as a matter of fact for the operator to hold the apparatus in one hand through its body 2 and to make the nose of said apparatus follow exactly the outline of the molded part by causing its slot 12 to slide over the section to be trimmed. By reason of the outer outline given to the cage section 8, it is apparent that it is possible to follow readily and uniformly the outline of even very sinuous articles.

It should be remarked that at protecting hood 13 covers the head of the apparatus and conceals thus the knives. The protective cap 13 at its lower part is not completely closed against the outer edge of sections 8 and 8b. Actually, it is curved at portions 14 and 14b to form lugs constituting openings 15 and 15b. Thus, when the knives 7 are rotated they function as fan blades causing the suction of air inwardly through the opening 15 and the expulsion of air and cuttings through the opening 151). The apparatus is therefore cooled at the same time as cuttings are discharged.

Obviously, my invention is by no means limited to the sole embodiment of a trimming apparatus which has been disclosed hereinabove by way of a mere exemplification and it covers in fact all of the modifications thereof falling within the scope of the accompanying claims; in particular said apparatus is suitable for the trimming of cast articles made of soft metals.

What I claim is:

1. An apparatus for trimming articles of rubber, plastic tem including at least one knife, means driving said blade system into rotation at a high speed, a casing inside which said blade system is revolubly carried and including two independent parts separated by a radial slot of adjustable breadth and forming together a counterblade the inner outline of which is arcuate and forms part of a circle tangent to the circle described by the ends of the revolving knives at a point coinciding with said slot and having a diameter slightly larger than that of the said circle, said slot being adapted to be engaged by the burrs which are to be removed from the article to be trimmed.

2. An apparatus for trimming articles of rubber, plastic material and soft metals, comprising a rotary blade system including at least one knife, means driving said blade system into rotation at a high speed, a casing inside which said blade system is revolubly carried and including two independent parts separated by a radial slot of adjustable breadth and forming together a counterblade the inner outline of which is arcuate and forms part of a circle tangent to the circle described by the ends of the revolving knives and having a diameter slightly larger than that Of the said circle, the breadth of said slot ranging between about 1 and 10 millimeters, said slot having one edge registering with the radius perpendicular to the tangent to the two circles at their point of tangency for engagement of said slot by burrs to be trimmed oil.

3. An apparatus for trimming articles of rubber, plastic material and soft metals, comprising a rotary blade system including two knives, a common plate for said knives, a hollow handle revolubly carrying said plate inside it, a yielding transmission extending through the handle and controlling the rotation of the plate, a casing rigid with the handle inside which said blade system is revolubly carried and including a section forming a counterblade the inner outline of which is arcuate and is a part of a circle tangent to the circle described by the ends of the revolving knives and having a diameter slightly larger than that of the last circle, said counterblade section being provided with a radial slot in substantial register with the point of tangency between the two circles, said slot being adapted to be engaged by the burrs which are to be removed from the article to be trimmed.

4. An apparatus for trimming articles of rubber, plastic material and soft metals, comprising a rotary blade system including a plurality of knives, means driving said blade system into rotation at a high speed, a casing inside which said blade system is revolubly carried, provided with at least one exhaust port in register with the blade system and including a section forming a counterblade the inner outline of which is arcuate and is a part of a circle tangent to the circle described by the ends of the revolving knives and having a diameter slightly larger than that of last mentioned circle, said counterblade section being provided with a radial slot in substantial register with the point of tangency between the two circles, said slot being adapted to be engaged by the burrs which are to be removed from the article tobe trimmed, the blade system acting as a fan cooperating with the ports in the casing to suck cooling air into the latter and to project centrifugally the waste material out of the casing.

References Cited in the file of this patent UNITED STATES PATENTS 2,508,570 Graves May 23, 1950 

